If you’re watching TV in your den while a thunderstorm rages outside, and you have to hold an umbrella to keep the rain off your head, that’s one clue that you need a new roof. Cascades of water dripping into strategically placed buckets throughout your house, or streaks and stains creeping down walls are obvious signs of a leak, and ignore it as long as you can, but a leak almost never stops by itself.

Other signs of roof damage are more subtle, according to Tony Tyrrell, general manager of administration for Ark Roofing in Memphis. “Look for the little granules in your gutters or on the ground, curled edges on shingles, or missing or broken shingles,” he says. “Cracks in the valleys, the troughs where roof planes meet, can be other signs.”

A new roof isn’t sometimes as easy as adding new shingles. Sometimes the old roof has to come off, all the way down to the bare decking. Local building codes specify that homes can have only two layers of shingle roofs, because most houses aren’t designed to carry any more weight than that.

Removing an old roof practically doubles the cost, but often it’s worth it, because it gives workers the chance to replace rotten or warped decking, and install new, higher-quality underlayers of tarpaper and synthetic materials that improve leak resistance and even thermal efficiency.

In recent years, an increasingly popular roofing material is galvanized steel. “Metal is better able to withstand the elements than just about any other material.” – Ken Buchinger

When choosing a roof, Tyrrell says that “composition shingles are still the most cost-effective materials for most homes.” Most of these are composed of tiny stone granules, which provide, color, add strength, and resist damaging ultraviolet light. These are bonded to a “scrim sheet,” the thick layer attached to the house. Years ago, basic roof colors were red, green, gray and shades of brown, “but nowadays customers can choose just about any color they want.”

Standard three-tab shingles are the least expensive — generally costing about $75 for 100 square feet, but “architectural shingles” — with an extra dimension that gives each shingle more texture — are increasingly popular.

“Since they are thicker, these usually have a longer life,” says Tyrrell, “and they are designed to mimic other, more expensive roofing systems, like cedar shakes or slate.”

If your home is designed to carry the extra weight, Ark Roofing and other companies around town can install genuine slate shingles, wooden shakes, and even rows of colored tiles. “For the most part, however, homeowners prefer composition shingles,” he says, “and if they are properly installed, they can last anywhere from 20 to 30 years, depending on the warranty from the manufacturer.”

In recent years, synthetic materials have also gained popularity, and in the Ark showroom Tyrrell shows banks of slate and cedar molded from colored and textured plastic. From a distance, they look like the real thing. “Fading used to be a problem with these,” he says, “but manufacturers have improved on the quality of these products, so you can have the look of a slate roof without the weight or cost.”

In recent years, an increasingly popular roofing material is galvanized steel. “Metal is better able to withstand the elements than just about any other material,” says Ken Buchinger, vice president of business development for Metal Depots, a Houston-based firm that recently opened a facility in Memphis. “It can last 40 years or longer, it’s sustainable since it’s usually manufactured from 40 percent recycled materials, and it’s 100 percent recyclable when it’s finally time to be replaced.”

Other advantages include fire resistance, strength, and even energy efficiency, since the metal reflects back much of the radiant heat from the sun. Though metal roofs can be copper, aluminum, or even zinc, the most common product is galvanized steel.

As with shingles, “hundreds of colors are available,” says Buchinger, and though years ago fading was an issue with certain metal products, “the paint is now baked on, and warranties are now available for up to 40 years.”

Metal roofs can be applied to almost any home, and Buchinger points out that metal can be used when the pitch of the roof is too steep to hold shingles and heavier products. It can even be installed over an existing shingle roof, though spacers are often used so any curling or warped shingles won’t affect the flatness of the metal sheets.

“It can last 40 years or longer, it’s sustainable since it’s usually manufactured from 40 percent recycled materials, and it’s 100 percent recyclable when it’s finally time to be replaced.” – Ken Buchinger

And if you’re envisioning bland strips of grey steel, think again. Metal roofs are available in various styles and textures, and can even be manufactured to duplicate the look of conventional shingles.

Regardless of the material selected, as with any home improvement project, proper installation is key to the success and longevity. Roofing is a difficult task, and flashing — installing the copper or sheet metal trim that seals shingles around chimneys, gables, and other protrusions — requires a skilled craftsman. The best roof in the world is worthless if the edges aren’t sealed properly, as anyone who has tried to trace the source of a leak can tell you.

“Proper installation is definitely key,” says Tyrrell, “but homeowners also need to hire a roofer that knows and follows the manufacturers’ requirements for whatever materials they are using, whether it’s regular composition shingles or other materials. They have to use the proper base material, they have to use the proper fasteners, or that 20-, 25-, or even 30-year warranty will be null and void.”

When choosing a roofer, first of all we suggest considering the companies listed on page 95 of this issue. After that, Tyrrell suggests that homeowners get detailed estimates from at least three companies. Check their business history with the Better Business Bureau. Look up customers’ comments on Angie’s List, a website that lists local contractors. Ask for references from the companies you are considering, and then go look at the work they did on those homes.

Above all, ask questions. If you have a special challenge, such as a stone chimney (often difficult to seal properly), or a flat roof (a variety of materials can be used here), ask how the company plans to tackle that problem.

Also, find out exactly how the roofer plans to protect your bushes or flowers while the work takes place — especially important if workers will be shucking off chunks of old roof and hundreds of rusty nails.

“A new roof is a major project that you will live with for years,” says Tyrrell, “so above all else, be an informed consumer.”